Ignore plural cases of units for now

[This PR](unicode-org/cldr#474) added information about cases for pluralization of units.
This code was not ready for that, and started returning whichever happened to be that last case in the section.

For now, we'll just return the case-less version as we always did.

lib/cldr/export/data/units.rb

@@ -28,6 +28,7 @@ def units(node)
 
         def unit(node)
           node.xpath("unitPattern").each_with_object({}) do |node, result|
+            next result if node.attribute("case") # Ignore cases for now. We don't have a way to expose them yet.
             count = node.attribute("count") ? node.attribute("count").value.to_sym : :one
             result[count] = node.content unless draft?(node)
           end